Eumelanin is a black-brown pigment, and pheomelanin is a red-yellow pigment ... cause early greying because they just coat the hair strand without changing its structure. However, permanent ...

and there are two main forms of hair pigment. There's eumelanin and pheomelanin. Eumelanin is what we see in brunettes and darker-haired people, and pheomelanin is what we see in blonds and redheads.